Sheep Milk: Environment

There is little knowledge about the environmental impacts of dairy sheep. Evidence is required to support the reputation of sustainability and assess whether dairy sheep milking may be a suitable land use in nitrogen-stressed catchments.

Research was undertaken to quantify some of the potential environmental effects of dairy sheep production systems in New Zealand. The four goals were:

1. Quantify nitrogen losses to water
2. Estimate the intensity of nitrogen and greenhouse gas emissions
3. Characterise effluent and refine good management practice guidelines
4. Refine farm system models

Two experiments were conducted to estimate nitrate leaching beneath grazing sheep, in two contrasting soil types. For lighter soils, the porous ceramic cup method was used, and for the heavier soils, hydrologically isolated plots.

We sampled effluent from ponds on a range of sheep milking farms to characterise the nutrient content.

A nitrogen balance model was used to investigate nitrogen flows within a farm as well as inputs and outputs from a farm.

We used desktop-based calculations to estimate greenhouse gas emissions (GHG) from real farm scenarios.